Regulating system



March 24, 1953 H, L, PRESCOTT 2,632,879

v REGULATING SYSTEM March 24, 1953 H. l.. PRI-:SCOTT 2,632,879

REGULATING SYSTEM Filed Aug. 19, 1950 4 Sheets-Sheet 2 F192' HeBrYber L.Pres'cott.

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March 24, 1953 Filed Aug. 19, 195o H. L.. PRESCOTT REGULATING SYSTEM 4Sheets-Sheet 3 March 24, 1953 H. l.. PRI-:SCOTT REGULATING SYSTEM 4Sheets-Sheet 4 Filed Aug. 19, 195o INVENTOR lObj WITNESSES:

Patented Mar. 24, 1953 UNITED STATES PATENT OFFlCE REGULATIN G SYSTEll/IApplication August 19, 1950, Serial No. 180,409

4 Claims.

This invention relates to electrical regulating systems, and inparticular to regulating systems utilizing a plurality of step typeregulators connected in parallel circuit relation for supplying a commonload.

Where a plurality of tap changing regulating transformers are connectedin parallel relation for supplying a common load, it is desirable thatsuch regulators be kept in step in order that circulating currentbetween the different tap changers will not cause excessive heating andreduce the output capacity oi the regulating transformers. Differentsystems have been developed heretofore in attempts to keep theregulators in step but they have had different operating disadvantages.For example, one known system initiates the operation of all of the tapchanging regulators simultaneously but if one unit gets out of step, allof the units are locked out requiring the attention of an operator torestore the units to operation.

An object of this invention is to provide, in a regulating systemutilizing a plurality of step type regulators connected for paralleloperation, for so controlling the sequence of operation that theregulators are maintained not more than one step apart during automaticregulating operations.

Another object oi this invention is to provide, in a regulating systemutilizing a plurality of step type regulators connected for paralleloperation, for so interconnecting the controls of the dierent regulatorsas to render one a master unit and the others follower units and tomaintain the regulators not more than one step apart during automaticregulating operations.

A further object of this invention is to provide, in a regulating systemutilizing a plurality of step type regulators connected for paralleloperation, means for selecting one of the regulators as a master unitand the others as follower units and of means for electing a positivelockout to maintain the regulators not more than one step apart duringautomatic regulating operations.

A more specific object of this invention is to provide, in a regulatingsystem utilizing a plurality of step type regulatorsconnected forparallel operation, means for selecting one of the regulators as amaster unit and the others as follower units with means for effecting apositive lookout to maintain the regulators not more than one step apartduring automatic regulating operations and means for cooperating withthe selective means for effecting a manual control of any one of theregulators without affecting the automatic control of the otherregulators.

(Cl. S23-43.5)

Other objects of this invention will become ap-- parent from thefollowing description when taken in conjunction with the accompanyingdrawings, in which:

Figures 1, 2, 3 and 4 form a composite drawing when Figs. l and 2 aredisposed side by side and Figs. 3 and 4 are disposed side by side withtheir upper edges butting the lower edges of Figs. 1 and 2,respectively, the composite drawing illustrating diagrammatically thecircuits and apparatus embodying the teachings of this invention.

Referring to the composite drawing, there is represented threeregulating units l0, I a, and lb, each of the units being illustrated inblock form and connected in parallel relation for supplying a commonload l2 from a three-phase alternating-current power system representedby the conductors I4, IB and I8. Each of the units I0, I 0a and |01) issubstantially identical as to components, units l0 and I 0a beingillustrated in detail, whereas unit b is merely illustrated in blockrepresentation only. For the purpose of simplifying the description ofthe components comprising the entire system, the components of unit I0only will be described in detail, it being understood that likecomponents of unit I0c1r will be similarly identied by the same numberwith the sux a appended thereto. Likewise, if the components of unitIllb were to be shown, they would be similarly identified by the samenumber with the sufx b appended thereto.

Each of the units includes a tap changing regulating transformer orregulator having the primary windings thereof connected to be suppliedfrom the conductors i4, i6 and I8.' The secondary windings 22, 24 and 26of the tap changing transformerare each provided with a plurality oftaps 28 disposed to be selectively engaged by a movable contact member14 positioned in response to operation of a suitable motor operatingmechanism represented by the motor 30. As illustrated, the secondarywindings of the transformer 20 are connected by conductors 32, 34 and 36to supply the load I2, the secondary windings being provided with aneutral point 38. The motor operating or control system for the motor isdisposed to be connected by a three-pole switch having the switchingmembers 42, 44 and 46 thereof for engaging xed contact members toconnect the control system to conductors 32, 34 and a neutral conductor48 which is connected to the neutral point 38 of the secondary windingsof the tap changing regulator.

In order to control the operation of the motor 3l? in response to adeviation of the quantity which is to be regulated, a primary relay isillustrated as being connected through a potential transformer s2 acrossthe load conductor 32 and a neutral conductor 5l." which is disposed tobe connected by the switch le to the conductor 43, whereby the primaryrelay 50 will be enersized to aetuate its movable contact member 56 intoengagement with contact members 5S or |30 depending upon the directionof the deviation. The primary relay 5U thus is disposed to initiate thecontrol of the operation of the motor 3|) in one or the other directionsby energizing one or the other of time delay or selective relays 62 or64 which, in turn, control secondary relays |56 and 58, respectively,the secondary relays being disposed to control the operation of motorcontrolling relays En and. l2, respectively, as will be described morefully hereinafter.

The motor 30 is connected through a suitable gear drive (not shown) tooperate the switch contact members 'it for simultaneously engagingcorresponding contact members .23 of the secondary windings 22, 2li and26'and simultaneously with a movement of the contact members 'le onestep to drive a pair of cam members 'E5 and 'i8 one revolution for eachstep of the movable switch contact members le, The cams 'Z6 and 'I8 aredisposed to control predetermined switching operations. Thus the cam l5,when the movable switch contact members 'M are in engagement withcorresponding contact members 2d of the secondary windings, maintains acooperating contact member 30 in a circuit interrupting position. Uponmovement of the motor 39, and consequently the cam l, the contact member80 is actuated to a circuit closing position during the revolution ofthe cam l.

The cam 18 as illustrated is disposed to drive a Geneva gear 82, 1A of arevolution for each revolution of the cam 18, to actuate a series of cammembers 84, 8S, 88 and et, 1A; of a revolution to control the switchingoperation of sets of contact members associated therewith. Thus themovement of the cam member 84 controls the switching operation ofcontact members 92, 94 and 96, cam B controls the switching operation ofcontact members 93, I and le?, cam 88 controls the switching operationsof contact members |04, |05 and Hi8, and cam Sil controls the switchingoperations of contact members l Ill, l2 and H4, the purpose of whichwill be more fully explained hereinafter.

Associated with each of the control mechanisms is a master controller HBhaving three sets of contact members disposed thereon in the positionsindicated respectively l, 2 and 3 for engaging cooperating Xed contactmembers positioned relatively thereto, The position 1 of the controllerI I6 is provided with contact members H8, |20, |22, |24, |26 and |28 inalignment thereon for engaging cooperating iixed contact members when itis desired to have the controlling yunit associated therewith as themaster unit where a plurality of the units are to be operated inparallel. The position 2 has a plurality of contact members |30, |32,|34, |36, |38 and i4@ in alignment therewith for engaging iXedcooperating contact members when it is desired to have the controlmechanism of the unit associated therewith operate as a follower unit.On the other hand, the position 3 is provided with contact membersV |42,|44, Ult, |48 and |5|`B for engaging iixed cooperating contact memberswhen it is desired to operate the control mechanism of the associatedunit independently of the other tap changing regulators which areconnected in parallel to supply the load I2. The master controller ||6is disposed, as illustrated, to cooperate with the contact membersactuated in response to a movement of the Geneva gear 82 to control thesequence of operation of the regulating units, as will be described morefully hereinafter.

In order to condition the control system for automatic operation ormanual operation, a controller |52 having a pair of contact members |54and |55 is `associated with the time delay relays E2 and 64 and disposedfor manual operation, whereby the contact members |54 and |56 engage xedcooperating contact members for establishing circuits for eitherautomatic operation or manual operation. When the controller |52 ismoved so that its contact member |55 engages its cooperating xed contactmembers, manual control of the energize-tion of the secondary relays 66and 58 may be effected by means of another controller |58 having contactmembers Ii'i and |62 thereon for engaging fixed cooperating contactmembers to selectively control the energization of the relays 65 and 68.

An auxiliary switch |66, and |6611 is illustrated for each of the unitsl0 and Illa, it being understood that a similar switch |64?) (not shown)will be utilized in the unit Ib to provide a complete circuit for theparallel connected units when the switch of the last unit is in thecircuit closing- `position, as will be described more fully hereinafter.The auxiliary switch |64 and ia will not be utilized as long as the unitIlib is the last of the follower units of the parallel connected systemsbeing controlled. However, if unit lila is rendered the last unit of thefollower system and unit Il) is rendered the master unit, as will bedescribed hereinafter, then the switch lla will be manually operated toits circuit closing position to provide a closed circuit. In actualpractice, where twc or more units are to be connected for sequentialoperation, the switches |54, Milla, etc. may be omitted and a permanentconnection substituted therefor in the last unit, as for example, inunit Illb where three units are connected for sequential operation orwhere unit I0 or ma is disposed for independent operation.

For the purpose of simplifying the explanation of the operation of theregulating system of this invention, it will be considered that only twounits iD and ma are connected for parallel operation, although it willbe understood that unit lllb and additional units could be added, andthat the sequence of operation of It?) and any other additional unitswill be the same as that which is to be described for unit lila.With'the switches di) and Illia moved to circuit closing positions andwith the master controller H6 of the unit Ill positioned whereby thecontact members of position l engage the cooperating xed contactmembers, the unit lll is established as a master unit. The mastercontroller ||6a of the unit lila is then positioned whereby the contactmembers in the position 2 will engage the cooperating Xed contactmembers and the switch lelie will be moved to a circuit closingposition, whereby the unit lila is established as a follower unit tofollow the operation of the control for unit ill. Likewise, thecontroller |52 of unit l is actuated so that its contact member I5@engages its cooperating iiXed contact members to condition the systemsof both units 'for automatic operation.

Assume that the tap changing-regulators 20 and 20a are in step forsupplying a load l2 and that for some reason the load |2 changes withthe result that the quantity which is to be regulated changes. Thus, forexample, if the voltage of the system is to be maintained and thevoltage should decrease, then the primary relay 50 of unit senses thechange or deviation of the quantity to be regulated and .is so energizedthat its movable contact member 58 engages the xed contact member 5B toestablish an energizing circuit for the energizing winding |68 of therelay 62. This circuit may be traced from the neutral conductor 54through conductor |58, contact member 02, conductor |18, contact member82a of the unit Illa, conductor |a, the shorting switch I84a, conductor|14, contact member |28 of the master controller H8, conductors |18 and|18 through the contact member |54 of the controller |52, energizingwinding |86 of the time delay relay 82, contact members 58 and 56 of theprimary relay 50 and conductors |88 and |84 to the closed switch 44 andthe load conductor 34.

When the time delay relay 82 is thus energized, if the deviation ismaintained for a predetermined period of time, the time delay relay 52is actuated so that its contact member |88 establishes an energizingcircuit for the secondary relay 66. This circuit extends from thecontact member |54 of controller |52 through the contact member |88 oftime delay relay 82, conductors |98 and |92, the energizing winding |94of the secondary relay 86 and conductor |84 to the closed switch 44.When the secondary relay 85 is thus energized, its movable contactmember |98 is actuated to a circuit closing position to establish anenergizing circuit for the motor control relay 18 which extends from theneutral conductor 54 through conductor |98, the energizing winding 200of the motor control relay 7U, conductor 282, the contact member |98 othe secondary relay 85 and conductor |84 to the closed switch 44.

When the motor control relay i5 is thus energized, its contact members284 and 288 are actuated to circuit closing positions and its contactmember 288 is actuated to a circuit interrupting position. When thecontact member 258 is thus actuated to its circuit closing position, asignal lamp 2|8 is lighted, the contact member 258 establishing asignaling circuit extending from the neutral conductor 54 through thelamp 2|8, conductor 2|2, contact member 285 `of the motor control relayl0, conductor 262, contact member |95 of the secondary relay andconductor |84 tl the closed switch 44. At the same time, the contactmember 284 of the motor control relay 'I8 closes and establishes acircuit to eiect operation of the motor 30, which circuit extends fromthe load conductor 34 through the closed switch 44, conductors |84, |88and 2|4, contact member 284 of the motor control relay 18, one of thewindings of the motor 38, cl-osed switch 42 to the load conductor 32,whereby the motor is so energized as to effect an operation of the tapchanging switch contact members 'i4 in a direction to so change theconnection to the taps 28 as to eiect an increase in the Voltage acrossthe load conductors 32, 34 and 38.

l/Vhen the motor 30 is thus energized, as soon as it starts to operate,cams l5 and 'i8 are operated to eiect switching operations. Thus cam 1Bis moved sun'iciently to permit the contact member 88 associatedtherewith to move to a circuit closing position to establish a holdingcircuit ior the motor control relay 'l0 to insure a one-step operationof the motor 30 even though the primary relay 50 is deenergized duringthe movement of the tap changing switching contact members 14. Thisholding circuit extends from the neutral conductor 54 through conductor|98, energizing winding 208 of the relay 10, conductor 202, contactmember 205 of the relay 10, conductor 2 |2, contact member 80 associatedwith the cam 18 and conductors 2|6 and |84 to the closed switch 44.

At the same time, the Geneva gear 82 is driven to effect a turn of thecams 84, 88, 88 and 90, whereby the contact members 82, 84 and 88associated with the cam 84 are moved to circuit interrupting positionsand contact members 98, |00 and |82 associated with the cam 88 are movedto circuit closing positions. In practice, the cams 84, 86, 88 and 98are of a size and shape with respect to the cam 78, that the contact 88moves to a circuit closing position before operation of the contactmembers associated with cams 84, 88, 88 and 08 is effected. The movementof the contact member 82 interrupts the energizing circuit for thewinding |84 of the secondary relay 56, whereby the secondary relay 88 isdeenergized and, upon completion of the movement Iof the cam 76representing a one-step operation of the tap changing switch contactmembers 14, the holding circuit for the motor control relay 18 isinterrupted and the motor 38 is no longer energized to effect furtheroperation of the tap changing switch Contact members 74.

When the contact members 88, |00 and |02 of the unit I0 are actuated tocircuit closing positions through the operation of the cam 88, anenergizing circuit is established for the secondary relay 68a of theunit |011 to initiate operation of the motor 30a. This energizingcircuit may be traced as extending from the neutral conductor 54 of theunit I8 .through the contact member |26 of the master controller H6,conductor 2|8, contact member |00, conductor 220, contact member |20 ofthe controller ||6, conductor 222, contact member I 34a of the mastercontroller ||6a, the closed contact member 98a, conductor 224a, contactmember l 40a of the controller ||6a and conductor I82a to the energizingwinding 94a of the secondary relay 88a, conductor |84a and closed switch44a to the load conductor 34a.

When such a circuit is energized, the secondary relay 88a is soenergized that its contact member |98 is moved to a circuit closingposition to establish an energizing circuit for the motor control relay18a. This circuit extends from the neutral conductor 54a throughconductor I98a, energizing winding 288:1 of the motor control relay 10a,conductor 282:1, contact member |96a of the secondary relay 88a andconductor |84a to the closed switch 44a.

When the motor control relay 10a is thus energized, its contact members284a and 20811 are actuated to a circuit closing position and thecontact member 208e thereof is actuated to a circuit interruptingposition. The movement oi contact member 208e establishes the signallight circuit for lamp 2|8a in the same manner as closing the contactmember 206 of the motor control relay 10 of unit l0 establishes thesignaling circuit. At the same time, the contact member 204a establishesthe motor energizing circuit which extends from the closed switch 44athrough conductors |84a and 2|4a, contact member 2040: of the motorcontrol relay 10a, a winding of the motor 30a through closed switch 42ato the load conductor 32a. When the motor 30a is .thus energized, iteffects the Operation of the .tap changing contact members 'Ma from oneof the Itaps 28 to an adjacent tap in a direction to eifect an increasein the voltage across the load conductors 32a, 34a and 36a.

The movement of the motor 30a also effects a simultaneous movement ofthe cams 76a and ita, whereby a holding circuit is established for theenergizing winding 200m of the motor control relay a to maintain themotor energized to effect a one-step movement of the tap changingcontact members 'Md regardless of whether or not the secondary relay ismaintained energized. This holding circuit extends from the neutralconductor 54a through conductor |9912, energizing winding 200:1 of themotor control relay 19a., conductor 202e, contact member 206er,conductor 2|2a, contact member 80a and conductors Zita and |84a to theclosed switch 45a.

At the same time that the cam ma is actuated, the cam 70a is alsoactuated to effect a 90 movement of the Geneva gear 82a with the resultthat the cams 94a, 86a, 88a and 90a are moved 90 to effect a switchingmovement of the contact members associated therewith. Thus as cam 84a ismoved 90, ythe contact members 92a, 94a, and 96a are actuated to circuitinterrupting positions and substantially simultaneously therewithcontact members 98a, |00a and |02@ associated with the cam 86a areactuated to circuit closing positions. As is evident from the drawingthe cam 34a permits movement of contact member 92a to an open circuitposition prior to the actual actuation of contact member 93a by the cam35d to a circuit closing position.

The movement of the contact member 96a associated with the cam 34a tothe circuit interrupting position interrupts the energizing circuit ofthe secondary relay 96a with the result that after the motor 30a hasoperated sufficiently to effect a one-step change in the positioning ofthe tap changing contact members 'ida and the cam 16a is operated onerevolution to eifect a circuit interrupting operation of the contactmember 80a to interrupt the holding circuit for the motor control relayma, that the control circuit for the motor 30a, is interrupted and nofurther movement of ythe tap changing contact members 14a can beeffected until after the master control unit has operated to effect afurther step operation of ythe tap changing switch contact members 'lllassociated with the master unit i9.

If the primary relay 50 of the master unit I0 continues to be energizedso as lto demand a change in the setting of the regulator 29 to effect afurther increase in the voltage across the load conductors 32, 34 and3B, the ltime delay relay 52 is further energized by a similar circuitdescribed hereinbefore In this instance, the energizing circuit for thewinding |06 of the time delay relay 52 extends froml the neutraloonductor 54 through conductor |68, closed contact member 99 associatedwith the cam 86, conductor ZEP, closed contact member 99a associatedwith the cam 86a, conductor 226e, the closed switch IGM and from thencethrough `the identical circuit previously described for effectingenergization of the winding |66 of the time delay relay 62. When thetime delay relay 82 is thus energized and its contact member |83 is incircuit closing position, an energizing circuit for the winding |94 ofthe secondary relay 69 is established, as described hereinbefore, withthe eX- ception that the circuit extends through the conv.-

tact member 98, conductor 226, contact member 99a and conductor 2260i tothe closed switch |B4a.

When the secondary relay 96 is thus again energized, the motor controlrelay 'l0 is energized as described hereinbefore, to establish theenergizing -circuit for the motor 30 to eect an operation of the tapchanging contact members 14 .and at the same time establishing a holdingcircuit for the windingtll of the motor control relay to insure aone-step operation of the tap changing contact members M. At the sametime that the cam 'i6 is actuated to provide the holding circuit for themotor control relay 70, the Geneva gear 82 is again actuated to effect a90 tur-ning operation of the cams uit, 90, 88 and 90, whereby thecontact members 99, |00 and |522 are actuated to circuit interruptingpositions and the contact members lud, idd and |08 are actuated tocircuit closing positions.

Since the contact vmember 98 is now in the circuit interruptingposition, it is impossible to establish the energizing circuit for thetime delay relay 62 or the energizing circuit for the secondar-y relay96. However, since the contact member |30 associated with cam 88 is nowin the circuit closing position, a circuit is established extending fromthe neutral conductor be through the contact member 95 of controllerIE6, conductor Zl, contact member ifiii associated with cam 85, contactmember E22 of the master controller Ei, conductor 23u, contact member|39a of controller lita, contact member |02@ associated with cam 36d,conductor Zlc, Contact member leida of the controller lita, conductor|9212, energizing winding idea iof the secondary relay 6ta and conductorHifi-a to the closed switch 44a. When the secondary relay a is thusenergized, it establishes the energizing circuit for the motor controlrelay iba which, in turn, operates as described hereinloefore toestablish the energizing circuit for the motor E@ to effect an operationthereof to actuate the tap changing contact members Fila from one tapato another tap 28a in a direction to increase the voltage across theload conductors 32a, Sie and 39a. At the same time, the motor tuafunctions to drive the cams 'itc and 'ita to establish a holding circuit`olescribed hereinbefore for the motor control relay lim to insure aone-step operation of the motor 96a, the cam lila being operatedeffectively to actuate the Geneva gear 32d to move the cams lia, 86a,88a and Stia, 90 whereby the contact members 98a, luca, |97?. areactuated to a circuit interrupting position and the contact membersIiida, Etta and ltlic are actuated to a circuit closing position.

A similar step operation of the regulators 20 and 20a is obtained if theprimary relay 50 is stlll conditioned to call for an additional changein the setting of tap changing contact members ld to eifect an increasein the Voltage across the load conductors 32, Sli and 39. Thus if themovable contact member 5t of the relay 59 is maintained in circuitengaging position with the xed Contact member 58, an energizing circuitfor the winding ltd of the time delay relay 92 is established whichextends from the neutral conductor 54 through conductor its, closedcontact member ma associated with the @am es, conductor 232 closedcontact member loda associated with cam 88a, conductor 2326i, the closedswitch ic and from thence through the circuit previously described foreffecting energization of the winding |65. The movement of the timedelay relay t2 to actuate itscontactemembereld to acircuit closingposition similarly establishes an energizing circuit for the secondaryrelay 66 through the contact member |04, conductor 232, contact member|04a, conductor 232a and the closed switch |64a and from thence asdescribed hereinbefore to effectively energize the secondary relay 66 ofunit l0 to effect an operation of the motor control relay to establishthe energizing circuit for the motor 30 and thus eiect `a onestepoperation of the tap changing contact members 14.

Again the movement of the motor 30 establishes the holding circuit forthe energizing winding 200 of the motor control relay, as describedhereinbefore, and elects a 90 movement of the Geneva gear 82 to actuatethe cams 84, 86, 88 and 90, whereby the contacts |04, |06 and |08 areactuated to their circuit interrupting positions and the contact membersH0, ||2 and ||4 are actuated to their circuit closing positions. Themovement of the contact member |04 eiectively interrupts the energizingcircuits to the time delay relay`62 and the secondary relay 66, wherebywhen the motor has completed .a one-step operation of the tap changingcontact members 14, the control system for the motor 30 is eectivelydeenergized.

At the same time, the Contact member ||2 establishes a circuit to effectthe energization of the secondary relay 66a which circuit extends fromthe neutral conductor 54 through the contact member |26 of the mastercontroller H6, conductor 2|8, contact member ||2 associated with the cam90, lcontact member |24 of the master controller ||6 and from thencethrough conductor 236, contact member |30a of the master controller||6a, closed contact member |08a associated with the cam 88a, conductor224a, contact member |04a of the controller ||5a and from thence throughthe energizing winding |84a, as described hereinbefore, to elect theenergization of the winding |94a of the secondary relay 66a.

When the secondary relay 66a is thus energized, it establishes theenergizing circuit for the motor control relay 10a, as describedherein'before, to establish the energizing circuit for the motor 30a toeffect operation thereof to actuate the contact members 14a one step. Aspreviously described, the motor 30a again drives the cams 18a and 18a toestablish the holding circuit for the motor control relay 10a and toeiect a 90 movement of the cams 84a, 86a, 88a and 90a, whereby thecontact members |04a, |06a and |08a are actuated to their circuitinterrupting positions and contact members Ilia, ||2a and ||4a areactuated to their circuit closing positions.

If the relay 50 is still energized to initiate a raise operation of themotor 30, the Geneva gear 82 is further operated to again drive theassociated cams in a direction to open contact members |10, ||2 and ||4and close contact members S2, 94 and 96 to initiate circuits to controlthe step operation of unit Ilia in a manner as described hereinbefore.The operation of the system could thus continue in one direction for asmany steps as there are contacts 22, etc. associated with theregulators. In practice limit switches (not shown) are provided forlimiting the extent o-f movement or switching operations of the tapchanging contact members 14, 14a, etc. in the raise and lowerdirections.

Assuming that the motor operating mechanism 30 and 30a has been operatedas described, so

that the tap changing contact members 14 and 14a are in a position tomaintain the voltage on the load conductors, and that the contactmembers ||0, ||2 and ||4 associated with the cam 90 and contact members||0a, ||2a and ||4a associated with the cam 90a are in circuit closingpositions as just described, if the load should change so that thevoltage across the load conductors increases, then the primary relay 50will be so energized that its movable contact member 56 is actuated intoengagement with the contact member 60 to establish an energizing circuitfor the winding 238 of the time delay relay 64. This circuit extendsfrom the neutral conductor 54 through conductor |68, contact member ||0associated with the cam 90, conductor 240, contact member ||0aassociated with cam 90a, conductor 240a, the switch |64a, conductor |14,contact member |28 of master controller i I6, conductors |15 and |18,contact member |54 of the controller |52, winding 238 of the time delayrelay 64, xed contact member 60 and movable contact member 56 of theprimary relay 50 and conductors |80 and |84 to the closed switch 44.

When the winding 238 is thus energized, the contact member 244 of thetime delay relay 64 is actuated to circuit closing position to establishan energizing circuit for the energizing winding 246 of the secondaryrelay 68. This circuit extends from the contact member |54 of thecontroller |52 through the contact member 244 of the time delay relay64, conductors 248 and 255, energizing winding 246 of the secondaryrelay 68 and conductor |84 to the closed switch 44.

When the secondary relay 08 is thus energized, its contact member 252 isactuated to` a circuit closing position to establish an energizingcircuit for the winding 254 of the motor control relay 12. This circuitextends from the neutral conductor 54 through the conductor |98,energizing winding 254 of the relay 12, conductor 255, contact member252 of the secondary relay 68 and conductor |84 to the closed switch 44.At the same time that the contact member 252 of the secondary relay 68establishes the energizing circuit for the winding 254 of the relay 12,the signal circuit is established to indicate that the motor isconditioned for operation. This signal circuit extends from the neutralconductor 54 through the lamp 2|0, conductor 2|2, closed contact member208 of the motor control relay 10, conductor 258, contact member 252 andconductor |84 to' the closed switch 44.

When the motor control relay 12 is thus energized, its contact member260 is actuated to a circuit closing position to establish an energizingcircuit for the other winding of the motor 30 to effect an operationthereof. This energizing circuit for the motor 30 extends from theclosed switch 44 through the conductors |84 and 2|4, contact member 260of the motor control relay 12, conductor 262, the winding of the motor30 and the closed switch 42 to the load conductor 32.

As the motor 38 is thus energized, it operates to effect a movement ofthe tap changing contact members 14 from one tap 28 to an adjacent tap28a and at the Isame time operates the cams 16 and 18 to establish aholding circuit for the winding 254 of the motor control relay 12 and toeffect a 90 movement of the Geneva gear ,82 and the cams 84, 86, 88 and90 associated therewith. As the cam 16 is actuated, its contact member80 establishes the holding circuit which actas-7a Y l1 extends from theneutral conductor 561 through conductor ist energizing the winding 254of the relay "i2, conductors 25S and 255, contact member 293 of therelay iii, conductor -2i2, contact member s@ and conductors 2li; and itto the closed switch Lili, thereby insuring that the motor will operateto eiect a one-step change in the setting of the contact members lil.

The movement of the cam iii actuates the Geneva gear 32 to effect amovement of the cams Bd, et, 88 and 9c, whereby the contact members lid,H2 and Hifi are actuated to their circuit opening position and contactmembers itil, it and its are actuated to a circuit closing position. Themovement of the contact member Si@ associated with cam t@ to opencircuit position interrupts the energizing' circuit for the time delayrelay 6d, and consequently for the motor control relay lil when themotor has operated to move the tap changing contact members ld one step.However, since contact memb er ict associated with the cam 88 is now ina circuit closing position, it establishes a circuit which extends fromthe neutral conductor d through the contact member E26 of a controllerIE6, conductor 2i8, contact member it associated with the cam t8,contact member 22 of the controller lib, conductor 23d, contact memberitta of the controller lita, contact member iiia associated with the camSita, conducto-r 2 lila, contact member Etta of the controller i ita,conductor 25de, energizing winding 2546: of the secondary relay 53a, andconductor iia to the closed switch alla, whereby the secondary relay 58ais energized. to actuate its contact member EZa to a circuit closingposition.

When the secondary relay i330; is thus energized, its contact member252e establishes a circuit which extends from the neutral conductor'bild through conductor ia, the energizing winding 25de of motor controlrelay lila, conductor 25de, contact member 252i; of the secondary relay68a and conductor ilia to the closed switch Elia to energize the motorcontrol relay 12a to actuate its contact member 2Std to a circuitclosing position.

The motor control relay '52a thus establishes a motor energizing circuitfor the motor Sila which extends from the switch Ma through conductorsEtta and Elia, contact member 26M of relay 72a, conductor SZa and theenergizing winding of the motor Sila to the closed switch ld to effectan operation of the motor Sila to actuate the tap changing contactmember Ma to move from one of the taps 28 to another. The operation ofthe motor 30d to move the tap changing contact members 'ida also effectsa movement of the cams ld and ita. rlhe cam 16a again operates to effecta movement of the contact member 80a associated therewith to a circuitclosing position to establish a holding circuit for the energizingwinding 25M of the motor control relay 72a. This holding circuit extendsfrom the neutral conductor 54a through conductor l98a, energizingwinding 25M of the relay 72a, conductors 2566i and 258a, contact member208e of the relay 76a, conductor 2me, contact member 80a and conductors2mm and E84@ to the closed switch lilla. t is, of course, to beunderstood that the signal circuit for the lamp illa is also establishedwhen the secondary relay 68av is energized to actuate its contact member25M to a circuit closing position, the signalling circuit extending fromthev neutral conductor 54a through the lamp Mila, conductor 2i2a,contact member 208er of the relay 'lii-afconduc'tcr 2586i."-

and iida are actuated to a circuit opening position, and Contact membersiiila, wsu and icf are actuated to a circuit closing position.

If the change in the Voltage across the load conductors occasioned bysuch operation of the tap changing contact members "M and 'Ma isinsufficient to effect the necessary reduction in the voltage across theload conductors, then the primary relay 50 of the unit iii is maintainedenergized with its movable contact 5t in engagement with the iixedcontact member S39, and since the contact members ill@ and iiifia are incircuit closing position, the time delay relay 64 is energized through acircuit extending from the neutral conductor 5d through conductor $68,contact member idd, conductor 323, contact member idi, conductor 232e,the closed switch Nida, and from thence through the circuit previouslydescribed for eiecting the energization of the winding 238 of the timedelay relay te. As the time delay relay et is thus energized to actuateits contact member 2M to a circuit closing position, the energizingwinding 2% of the secondary relay @il is again energized through thecircuit extending from the neutral conductor flthrough conductor itt,contact member iM, conductor 232, contact member Hella, conductor 23mand the closed switch lia and from thence through the circuit previouslydescribed. The energization of the relay SS causes the relay et tooperate to again effect the energization of the motor control relay l2to again establish the energizing circuit for the motor 3G to eect anoperation of the tap changing contact members TM.

Again the operation of the motor Sli also effects operation of the cams'it and 'i8 to establish the holding circuit previously described forthe energizing winding of the motor control relay 12 and to eiect asimultaneous operation of the cams 84, d5, 33 and 9K3 through an angleof 90, whereby the contact members idd, IE6 and His are actuated tocircuit interrupting positions and contact members Q8, iii@ and iti areactuated to circuit closing positions. As in the previous case, theoperation of the cams 8d, 86, 88 and 90 effects an interruption of theenergizing circuit for the winding of the time delay relay 64 andconsequently an interruption of the energizing circuit of the energizingwinding for the secondary relay 68 with the result that the motor willoperate only so long as the holding circuit is maintained uninterruptedby the operation of the cam 16.

As soon as the cam dii actuates its associated contact members intocircuit closing positions, the contact member i0@ associated therewithestablishes an energizing circuit for the Winding 2:36a of the secondaryrelay 68u of the unit wm This circuit extends` from the neutralconductor 54 through the contact member 26 of controller i i6, conductor2 i8, contact member iilii, conductor 220, contact member i2@ of thecontroller H5, conductor 222, contact member |34a of the controller iia,contact member Mita associated lith cam Mia, conductor 218e, contactmember lSa of the controller i Ita and from thence through the circuitpreviously described to eiectively energize the windings 2560i of thesecondary relay 69a and eiiect a movement of its contact member 252:1 toa circuit closing position. With the secondary relay 68a energized inthis manner, the motor control relay '12a is energized to establish themotor energizing circuits previously described to effect an operation ofthe motor 30a to actuate the tap changing contact members 14a to movefrom one of the taps 28a to another tap 25a in a direction to effect adecrease in the voltage across the load conductors supplied therefrom.Such operation of the motor 39a also effects a movement of the Genevagear 82a in a direction to operate the cams associated therewith toeiiect a movement of the contact members 154s, Hita and Hita associatedwith the cam 88a to a circuit opening position and the contact members98a, Milla, and m2o associated with the cam 89a to a circuit closingposition.

Similar operations of the units I and 19a will be apparent if theprimary relay 553 is still energized to demand an adjustment of the tapchanging regulators 29 and 29a to effect a further decrease in thevoltage across the conductors 32, 3d and SI5, it being noted that theinitial energizing circuit for the time delay relay $4 is eiectedthrough the circuit extending from the neutral conductor 54 throughconductor |58, contact member 9B 'associated with cam B, conductor 225,contact member 98o, conductor 22Go and the closed switch lte and fromthence through circuits previously described to effect the energizationof the time delay relay te. The operation of the system 4has beendescribed hereinbefore where such an energizing circuit has beenestablished for the time delay relay. Under such energized conditions,the secondary relay 98 is also energized to effect the energization ofthe motor control relay l2 to eiect an operation of the motor 39 in adirection to change the setting of the tap changing contact members 'i4l to effect a decrease in the voltage across the load conductors. Againthe Geneva gear 5.2 is driven by operation of the motor 39 to effect anoperation of the cams associated therewith to actuate the contactmembers t9, It@ and E92 to a. circuit opening position and the contactsQ2, 94 and 9E associated with the cam 84 to a circuit closing position.

Under such conditions of operation a circuit is established for thesecondary relay tta of unit Ita, the circuit extending from the neutralconductor 54 through the contact member i25 of controller HE, conductorZES, contact member S4 associated with cam Sli, contact member HB,conductor 25S, contact member 32a of the master controller lita, Contactmember Itter associated with the cam 86a, conductor Zita to the contactmember iSta of the controller lita and from thence through the circuitspreviously described for effecting the energization of the winding 246a.As previously described, when the secondary relay a is thus energized,contact member 25.211, establishes an energizing circuit for the motorcontrol relay i2@ to thereby establish an energizing circuit for themotor 39a and eiect the operation thereof to actuate the tap changingcontact members ida from one tap 28a to another tap 28a, in a directionto decrease the voltage of the conductors supplied therefrom. At thesame time the holding circuit for the motor control relay 72a, is alsoenergized by the operation of the motor 39a to effect a step operationof the motor and the Geneva gears 82a are driven to effect a 90 movementof the cams associated therewith, whereby the contact members 98a, laand l2a are actuated to circuit interrupting positions and the contactmembers 92a, 94a and 96a are actuated to circuit closing positions.

It is thus seen that where the units I0 and Ia or if additional unitslb, etc., are added to the system that by establishing the unit l0 asthe master unit through suitable setting of a master controller i i6 andthe other as follower units by setting the controllers IIBa, etc.thereof in position 2 as follower units, and closing the switch iia, ofthe last follower unit so as to provide a complete circuit when thecorresponding contacts of corresponding cams 84 are in circuit closingposition, that a. positive lockout of the master unit is obtained untilall of the follower units have been sequentially operated to adjusttheir tap changing contact members one step whereby the regulators aremaintained not more than one step apart during an automatic regulatingoperation of the tap changing regulators. Further, by controlling theoperating mechanism for tap changing motors in the manner described, itis seen that where all of the regulators are in step, the master unitonly is operated initially to effect a change in the setting of its tapchanging regulator. If one of the follower units is out of step, it maybe brought back into step by operating that unit independently as willbe explained more fully hereinafter. By maintaining all of theregulators not more than one step apart in this manner, it is seen thatcirculating currents will be reduced to a minimum and that there will besubstantially no power loss as between the different regulators.

in the automatic regulating operation described hereinbefore, it wasassumed that the unit i9' was the master unit and the unit Illa was thefollower unit. If instead of such an arrangement it is desired tocondition the unit la as the master unit and the unit I9 as the followerunit, then the controller Illia is moved so that the contact members ofposition 1 engage the corresponding xed contact members and thecontroller IIE is moved to a position where the Contact memberscorresponding to the position 2 thereof engage the fixed contact membersassociated therewith to thereby establish the unit Ita as the masterunit and the unit I0 was the follower unit. For purposes of simplifyingthe description, only one step of the operation where the unit Ia is themaster unit will be described.

Thus assuming that the tap changing regulators 20 and 20a are set and instep so as to maintain a given voltage on the load conductors if forsome reason the voltage should decrease, then the primary relay 59a ofthe unit lila is so energized as to actuate its contact member 56a` intoengagement with the contact member 58a. This establishes a circuit asdescribed hereinbefore from the neutral conductor 54 of the tap changingunit 29 through the conductor |68, contact member 92 associated with cam84, conductor Ht, contact member 92a, associated with cam 84a andconductor Illia, closed switch |6411, contact member I2Sa of thecontroller lla, conductors llia and |7811., contact member l54a,energizing winding Ia or" the time delay relay 62a, contact members 58aand 56a of the primary relay 5a, conductor la and [84a to the closedswitch 44a to effectively energize the time delay relay 62a. When thetime delay relay 62a is energized and its contact member 1880i isactuated to a circuit closing position, a circuit is established whichextends from the contact member lilla of controller I52dl through'thecontact member ISM, conductors Hita and 192e, the energizing winding tteof the secondary relay 5ta and conductor i 84a', to the closed switchGila to eiectively energize the secondary relay @6a. As the contactmember 5960.', of the secondary relay tta is actuated to its circuitclosing position, it establishes the energizing circuit for the inotorcontrol relay ltd, as described hereinbefore, to effect an operation ofthe motor 39a to actuate the tap changing contact members 'lila one stepin a direction to increase the voltage across the load conductorssupplied therefrom. At the same time, the cam lia operates to establishthe holding circuit so as to insure a onestep operation of the motorSila, as described hereinbefore.

' Simultaneously therewith, the Geneva gear 82a is driven to effect amovement of the cams 84a, 86a, Sta, and Sea to actuate the contactmembers 92a, .fida and Qta to a circuit interrupting position and toactuate the contact members 98a, I Die and 192e to a circuit closingposition. The operation of the contact member 92a 4to a circuitinterrupting position effectively interrupts the energizing circuits ofthe time delay relay 62a and the secondary relay tta.

' Since the contact member I @Ela is now in a circuit closing position,it effectively establishes a circuit which extends from the neutralconductor 54M through contact member Ifliid of the controller lita,conductor Elda, contact member I @da associated with the cam lita,contact member 129er of the controller Mba, conductor 222, contactmember I3@ of controller I i6, contact member 25 associated with cami3d, conductor 224, Contact member lit? of the controller IIS, conductor92, energizing Winding I9@ of the secondary relay-66 and conductor iddto the closed switch l to thereby effectively energize the secondaryrelay 6b to actuate its contact member it to a circuit closing position.As the contact member itt of the secondary relay E6 is thus actuated tocircuit closing position, it establishes the energizing circuit for themotor` control relay lil as described hereinbefore to eiiectivelyestablish an energizing circuit for the motor 30 to operate the motorSi) in a direction to actuate the tap changing contact members ld onestep in a direction to effect an increase in the voltage across the loadconductors supplied therefrom. As described hereinbefore, the motor 3Bis effective for actuating the cam i6 to establish the holding circuitfor the motor control relay 'i6 and at the saine time actuates the cam'F3 to operate the Geneva gear 82 to move the cams 8S, 85, 88 and Se toeffect a movement oi the contact members S2, ed and 96 to a circuitopening position and a movement of the contact members 98, IUS) and |52to a circuit closing position.

While only a one-step operation has been described with respect toconditions where the regulating unit Ita is established as the masterunit and regulating unit Id as the follower unit, it will be readilyappreciated that further step operation of the two units will beeffected in the same manner by suitably controlling the sequentialoperation of the cams associated with the Geneva gears 82a and S2inresponse to operation of the motors fiile and 3i), respectively, withwhich they are associated.

in all cases, the sets of contact members associated with the camsoperated by the Geneva gears 82a and 82 are effective upon operation ina sequential manner for rst locking out the master regulator unit andthen enectively establish-A ing circuits for effecting an operation ofthe follower unit and at all times to maintain such regulatingopera-tions within one step of one another.

The regulating system described has a further advantage that each of thetap changing regulators 2E, 29a, etc., operates from one position tothenext under the control of its own holding circuit and moto-r controlrelays so that any diiferences in the speed of the different tapchanging units will not interfere with obtaining the proper parallelingoperation. This will be especially appreciated when it is consideredthat the units are operated at all times within one step of each other.Further, as will be evident, there is no time delay between theoperation of the master unit and the operation of the follower unitsonce the motor for the master tap changer has been initiated foroperation so as to effect an operation of the cams associated with theGeneva gear 82 or the like. While each unit is complete so that it canbe operated independently of the other units which are connected forparallel control operation, all the units connected for the parallelcontrol operation are controlled from one voltage regulating primaryrelay so :that differences in the relay adjustments utilized with thedifferent regulating units will not affect the parallel operation.

While the operation has been described with respect to an automaticregulating operation with the units all operating in parallel, it is, ofcourse, to be understood that any one of the units may be operatedindependently of the other units either for automatic operation or for amanual control. For example, assume that it is desired to operate theregulating unit Ict independently of the regulating units Iii and lill)and still maintain regulator llb as a follower for the regulating unit.In such case, the master controller IIB of the regulating unit lil ismaintained in the position previously described with the contact membersof position l engaging the fixed contact members associated therewith toestablish the regulating unit Iii as the master unit. The controllerIiib (not shown) of the regulating unit i tb would then be positioned inthe position 2 to establish the regulating unit lill) as a follower unitfor operation, as described hereinbefore with respect to unit lila whenunit Ita was a follower unit for the master unit It. The units I0 andleb would then. continue to function in :the manner describedhereinbefore with respect to units I il and lila. v However, in order tocondition unit Illa for operation independently of the units I0 and Ib,the master controller l ISC: is then moved to a position where itscontact members Md, Mila, IlIGa, Hi8@ and Ia in the No. 3 positionengage the ixed contact members associated therewith to effectivelyshort conductors I'lla, 226m, 232e and Mita, so that operation of thecams 84a, 86a, 88a, and 96a has no effect with regard to establishing orinterrupting energizing circuits for the time delay relays 62 or bil.Thus it is seen that the contact members ilia, Milla, lilla and Mafunction to by-pass contact members a, 98a, |0411 and i lila with theresult that operation of cams a, 3811 88a and 96d has no effect on theoperation ofunits It and mb.

Under such conditions, the primary relay 5ta of the unit -I Ila isresponsive to the voltage across the conductors to actuate its movablecontact member 56a. into engagement with 'fixed contact members 580 or660 depending upon whether or not it is desired to operate the motor 360in a direction to raise or lower the voltage across the conductors 320,340 and 360. Assuming, for example, that the primary relay 560 isenergized in a direction to effect an increase in the voltage across theconductors then as the contact member 560 engages the Contact member560, a circuit is established which extends from the neutral conductor540 through the contact member ||J0y of the controller H60, conductor|180, contact member |540, energizing winding |660 of the time delayrelay 620, contact members 580 and 560, conductors |860 and |840 to theclosed switch 440. As the time delay relay 620 is energized to actuateits contact member |680 to a circuit closing position, it establishes acircuit eX- tending from the neutral conductor 540 through the contactmember |560 of the controller ||60 through conductor |180, contactmember `|540 of the controller |520, contact member |880 of the timedelay relay 620, conductors |960 and |920, energizing Winding |900 ofthe secondary relay 660 and conductor |840 to the closed switch 440 tothereby energize the secondary relay 660 and actuate its contact member|860 to a circuit closing position. The energization of th-e secondaryrelay 660 thus effectively establishes the energizing circuit for themotor operating relay 160, as

described hereinbefore, to effect its operation to establish theenergizing circuit for the motor 360 and thereby eect an operation ofthe motor 360 in a direction to drive the tap changing contact member'|40 in a direction to effect an increase in the voltage across the loadconductors. As in the previous operations described, as the motor 360 isoperated, the cam 'i60 is effective for establishing the holding circuitfor the motor control relay 16 so as to insure a one-step operation ofthe motor 300 before the energizing circuit therefor is interrupted.

If the energization of the primary relay 560, is such as to actuate itscontact member 560 into engagement with the xed contact member 660, thena similar energizing circuit is established from the contact member |540of the controller |520 through the energizing Winding v2380 of the timedelay relay 640 to effect an operation of the time delay relay andactuate its contact member 2440 into circuit closing position toestablish a similar energizing circuit for the winding 2460 of thesecondary relay 630. tends from the contact member |540 of thecontroller |520 through the contact member 2440. of

time delay relay 640, conductors 2680 and 2560 and the energizingWinding 2460 of the time delay relay 680 to the conductor |840 to soenergize the secondary relay 680 as to actuate its contact member 2520into circuit closing position. The secondary relay 580 is thus effectivefor establishing the energizing circuit for the motor control relay |20as described hereinbefore to actuate its contact member 2660 to circuitclosing position to establish an energizing circuit for the motor 300 tooperate the motor in a direction to actuate the tap changing contactmembers 'i140 one step in a direction to effect a decrease in thevoltage across the load conductor supplied by the regulator 260. As inthe previous instances, the operation of the motor 360 effects anoperation of the cam '|60 to establish a holding circuit for the motorcontrol relay '120 so as to insure a one-step operation of the motor 360regardless of the demands of the primary relay 560.

If instead of the independent automatic opera- This latter circuit ex-18 tion of the regulators hereinbefore described, it is desired tomanually control the operation of one of the tap changing motors, forexample motor 360, such an operation may be obtained by moving thecontroller |520 to a position where its contact member |540 is out ofcontact engag-l ing position with respect to its fixed contact membersand the contact member |580 is actuated to a circuit closing position toengage its cooperating iixed contact members. The contact member |560 ofthe controller |520 is thus connected by a conductor |180 through thecontact member |580 of the controller |160 to the neutral conductor 540.The contact member |56@ 01"' controller |520 is also disposed to beconnected by a conductor 2680 to a center xed tap on the manual operablecontroller |560. Then by operating the manual controller |560 so as toselectively actuate its contact members |620 and |660 into engagementWith the xed contact members associated therewith, energizing circuitsfor the secondary relays G60 and 680, respectively, are established.

Assuming, for example, that it is desired to manually control theoperation of the tap changing regulator 260 in a direction to increasethe voltage on the load conductors, then the controller |580 is moved toa position Where the contact member |620 establishes a circuit Whichextends from the neutral conductor 540 through contact member |560 ofthe controller |60, conductor |780, contact member |560 of thecontroller |520, conductor 2680, contact member |620 of the controller|560, conductor |620, energizing winding |90 of the secondary relay 660and conductor |340 to the closed switch 440. As the Winding of thesecondary relay 660 is thus energized, the contact member |960 of therelay is actuated to a circuit closing position to establish theenergizing circuit for the motor control relay 160 in a mannelvdescribed hereinbefore to thereby establish an energizing circuit forthe motor 360 to effect the operation thereof in a direction to actuatethe tap changing contact members to effect an increase in the voltageacross the load conductors. The holding circuit for the motor controlrelay '|60 is also established by operation of the cam as the motor 300is operated, so that even though the controller |580 is actuated to aposition Where its contact member |620 interrupts the energizing circuitfor the secondary relay 660, nevertheless the motor 360 will be operatedone complete step before its energized circuit is interrupted.

If it is desired to manually control the operation of the motor 360 toeffect a decrease in the voltage across the load conductors suppliedtherefrom, then the controller |580 is manually operated to a positionWhere its contact member |660 establishes a similar circuit extendingfrom the neutral conductorY 540 through contact member |560, conductor|180, contact member |560 of controller |520, conductor 2680, contactmember |660 of the controller |580, conductor 2500, the energizingWinding 2460 of the secondary relay 680 and conductor |840 to the closedswitch 440. The secondary relay 680 When thus energized operates in amanner described hereinbefore to effect the energization of the motorcontrol relay 1'20 to establish the motor energizing circuit and eiectan operation thereof in a direction to actuate the tap changing contactmembers '|40 in a direction to effect a decrease in the voltage acrossthe load conductors supplied therefrom. Again the cam '|60 is effectivefor estab- 19 lishing a holding circuit for the motor control relay 52aas described hereinbefore for maintaining the motor Eta energized toelect a one-step movement of the tap changing contact members Ma.

As will be appreciated, if it is desired to manually eiect and controlthe step-by-step operation of the units connected in parallel, one ofthe units, such as unit iii, is selected as the master unit and thecontroller H is moved to position 1. The controller 552 is then moved toits manual operation position where the contact member it@ engages itsassociated xed contact members to connect conductors l'iii and 258. Thenby moving the controller 58 to either the lower or raise position whereits contact members iti? and M52, respectively, selectively establishthe energizing circuits for windings 2st and 94, respectively, of thesecondary relays 68 and 66, respectively, the motor Se will be energizedas described hereinbefore to effect operation of the tap-changingcontact members 'it'. As the motor 3S is operated, cams i5 and '8 willbe turned in a direction depending upon whether the change is a lower orraise to automatically lock out the master unit lil and establish theenergizing circuits for the sequential operation of the follower unitslila and lub as described hereinbefore to effect the sequentialstep-bystep operation of the units and maintain the units not more thanone step apart. Thus, it is seen that the sequential step-by-stepoperation of the bank of units, which are connected for paralleloperation, can be manually controlled and effected as well asautomatically controlled. A

Thus, even though the controller |53 is positioned in either the raiseor lower position, after the motor 3d has effected a one-step operationoi contact members id, further operation of the motor 3d' of unit l@ inthe same direction is still dependent upon the follower action of themotors Bila, etc., effecting the sequential operation of the Genevagears 82a, etc., to again establish the initial energizing circuit forthe secondary relay et or es to thereby control the next step operationof the motor 3c and effectively lock out the motor Sil until after themotors a, etc., have sequentially effected a step-bystep operation ofthe regulator associated therewith.

While the independent operation of only oneA unit has been describedhereinbefore, it will be apparent that where a bank of N numbered unitsare utilized any number of the units from 2 in number up to N in numbermay be automatically operated in parallel, or that part of the units maybe operated in parallel and the remaining units may be operatedindependently of one another and independently of the paralleled units.The system is thus quite flexible in the control of the units.

I claim as my invention:

l. In a regulating system having a plurality of step type regulatorsconnected in parallel circuit relationship for supplying a common loadhaving a quantity to be regulated, the combination comprising, a loadcircuit, the step type regulators being electrically connected inparallel relationship to the load circuit, each of the parallelconnected step type regulators comprising a primary relay connected tobe responsive to the quantity to be regulated, a plurality of selectiverelays connected in circuit relationship in each step type regulator anddisposed for selectivo operation by its corresponding primary relay, aplurality of secondary control relays connected in circuit relationshipin each step type regulator disposed for selective operation by theprimary relays respectively, a plurality of motor control relaysconnected in circuit relationship in each step type regulator disposedto be operated by the secondary control relays respectively, a motorconnected in circuit relationship in each step type regulator disposedfor operation in a f predetermined direction in response to theselective operation of its corresponding primary relay, tap changercontact members disposed to be actuated by each motor to change thequantity to be regulated in accordance with the selective operation ofthe corresponding primary relay, a cam actuated switch mechanismdisposed to be actuated by each motor, an electrical circuit connectedto be controlled by the motor driven cam operated switch mechanism ofone step type regulator for initiating the operation of a second of theparallel connected step type regulators independent ofthe primary relayof the second step type regulator to effect actuation of a correspondingsecond set of tap changer contact members, the second step typeregulator being provided with an electrical circuit which after theactuation of the corresponding tap changer contact members functions toestablish an actuating circuit for the operation of the motor of the rstset of tap changer contact members thereby to effect a continuousoperation for an equal number of steps of the sets of tap changercontact members in sequential order until interrupted by the operationof the primary relay of the first step type regulator to function, and aplurality of manually operated drum controllers `disposed to heconnected incircuit relationship in the parallel connected step typeregulators to predetermine which steptype regulator will function firstand as a master regulatorand the order of the otherstep type regulatorsas followers, one drum controller being provided for each step typeregulator.

2. In a regulating system having a plurality of step type regulatorsconnected in parallel circuit relationship for supplying a common loadhaving a quantity to be regulated, the combination comprising, a loadcircuit, the step type regulators being electrically connected inparallel relationship to the load circuit, each of the parallelconnected step type regulators comprisingA a primary relay connected tobe responsive to the quantity to be regulated, a plurality of time delayrelays connected incircuit relationship in each step type regulator anddisposed for selective operation by its corresponding primary relay, aplurality of secondary control relays connected in circuit relationshipin Yeach step type regulator disposed for selective operation by theprimary relays respectively, a plurality of motor control relaysconnectedin circuit relationship in each step type regulator disposed tobe be operated by the secondary control relays respectively, a motorconnected in circuit relationship in each step type regulator disposedfor operation in a predetermined direction in response to the selectiveoperation of its corresponding primary relay, tap changer contactmembers disposed to be actuated by each motor to change the quantity tobe regulated in Aaccordance with the selective operation of thecorrespondingk primary relay, a cam actuated 'switch mechanism disposedto be actuated by each motor, an electrical circuit connected to becontrolled by the motor driven cam operated switch mechanism of one steptype regulator for iniating the operation of a second of the parallelconnected step type regulators independent of the primary relay of thesecond step type regulator to eiect actuation of a corresponding secondset of tap changer contact members, the second step type regulator beingprovided with an electrical circuit which after the actuation of thecorresponding tap changer contact members functions to establish anactuating circuit for the operation of the motor of the rst set of tapchanger contact members thereby to effect a continuous operation for anequal number of steps of the sets of tap changer contact members insequential order until interrupted by the operation of the primary relayof the rst step type regulator to function, a plurality of manuallyoperated drum controllers disposed to be connected in circuitrelationship in the parallel connected step type regulators topredetermine which step type regulator will function rst and as a masterregulator and the order of the other step type regulators as followers,one drum controller being provided for each step type regulator, andmanually operated switching means connected in electrical circuitrelationship in each of the step type regulators for controlling theoperation of the secondary motor control relays independent of theprimary relays and the time delay relays.

3. In a regulating system having a plurality of step type regulatorsconnected in parallel circuit relationship for supplying a common loadhaving a quantity to be regulated, the combination comprising, a loadcircuit, the step type regulators being electrically connected in parzallel relationship to the load circuit, each of the parallel connectedstep type regulators comprising a primary relay connected to beresponsive to the quantity to be regulated, a plurality of selectiverelays connected in circuit relationship in each step type regulator anddisposed for selective operation by its corresponding primary relay, aplurality of secondary control relays connected in circuit relationshipin each step type regulator disposed for selective operation by theprimary relays respectively, a plurality of motor control relaysconnected in circuit relationship in each step type regulator disposedto be operated by the secondary control relays respectively, a motorconnected in circuit relationship in each step type regulator disposedfor operation in a predetermined direction in response to the selectiveoperation of its corresponding primary relay, tap changer contactmembers disposed to be actuated by each motor to change the quantity tobe regulated in accordance with the selective operation of thecorresponding primary relay, a cam actuated switch mechanism disposed tobe actuated by each motor, a plurality of manually operated druincontrollers disposed to be connected in circuit relationship in theparallel connected step type regulators to predetermine which step typeregulator functions rst and as a master regulator and the order of theother step type regulators as followers, one drum controller beingprovided for each step type regulator, means provided on each motordriven cam actuated switch mechanism cooperative with its correspondingdrum controller for establishing electrical circuits in the parallelconnected step type regulaters for first locking out the masterregulator and then establishing a motor actuating circuit in thefollower step type regulator to effect an operation of the correspondingtap changer contact members after each operation of the tap changercontact members of the first operated step type regulator, an electricalcircuit connected to be controlled by the motor driven cam operatedswitch mechanism of one step type regulator for initiating the operationof a second of the parallel connected step type regulators independentof the primary relay of the second step type regulator to effectactuation of a corresponding second set of tap changer contact members,the second step type regulator being provided with an electrical circuitwhich after the actuation of the corresponding tap changer contactmembers functions to establish an actuating circuit for the operation ofthe motor of the first set of tap changer contact members thereby toeffect a continuous operation for an equal number of steps of the setsof tap changer contact members in sequential order until interrupted bythe operation of the primary relay of the rst step type regulator tofunction.

4. In a regulating system having a plurality of step type regulatorsconnected in parallel circuit relationship for supplying a common loadhaving a quantity to be regulated, the combination comprising, a loadcircuit, the step type regulators being electrically connected inparallel relationship to the load circuit, each of the parallelconnected step type regulators comprising a primary relay connected tobe responsive to the quantity to be regulated, a plurality of time delayselective relays connected in circuit relationship in each step typeregulator and disposed for selective operation by its correspondingprimary relay, a plurality of secondary control relays connected incircuit relationship in each step type regulator disposed for selectiveoperation by the primary relays respectively, a plurality of motorcontrol relays connected in circuit relationship in each step typeregulator disposed to be operated by the secondary control relaysrespectively, a motor connected in circuit relationship in each steptype regulator disposed for operation in a predetermined direction inresponse to the selective operation of its corresponding primary relay,tap changer contact members disposed to be actuated by each motor tochange the quantity to be regulated in accordance with the selectiveoperation of the corresponding primary relay, a cam actuated switchmechanism disposed to be actuated by each motor, a plurality of manuallyoperated drum controllers disposed to be connected in circuitrelationship in the parallel connected step type regulators topredetermine which step type regulator functions first and as a masterregulator and the order of the other step type regulators as followers,one drum controller being provided for each step type regulator, meansprovided on each motor driven cam actuated switch mechanism cooperativewith its correspending drum controller for establishing electricalcircuits in the parallel connected step type regulators for rst lockingout the master regulator and then establishing a motor actuating circuitin the follower step type regulator to effect an operation of thecorresponding tap changer contact members after each operation of thetap changer contact members of the rst operated step type regulator, anelectrical circuit connected to be controlled by the motor driven camoperated switch mechanism of one step type regulator for initiating theoperation of a second of the parallel connected step type regulatorsindependent of the primary relay of 23 the second step type-regulatorfto eeetaetuation of aeorresponding second set of tap changercontact members, the second-step type regulator beingfprovided with anelectrical circuit which after the actuation of the Corresponding tapchanger Contact members' functions to establish an actuating circuit forthe operation of lthe motor of the rst set of tap changer Contactmembers thereby to eect a continuous operation for an equal number ofsteps of the sets of 1 tap changer Contact lmembers in sequential orderuntil interrupted by the operation of the :prii mary relay of the rststep type regulator to function, and manually operated switching meansconnected in electrical circuit relationshipin each of the step typeregulators for controlling the operation of the secondary motor controlrelaysinlependent-of the primary relays and the time Vdelay relays.

HERBERT L. PRESCOTT.

REFERENCES CITED The following references are of record in the le ofthis patent:

UNITED STATES PATENTS Number Name Date 1,753,143 Farley June 10, 19301,909,068 Oglesbee May 16, 1933 FOREIGN PATENTS Number Country Date12,051 Australia Feb. 12, 1929 of 1928

